Technical Field
Embodiments described herein are related to the field of high-speed interface design, and more particularly to AC coupling techniques.
Description of the Related Art
Computing systems typically include a number of interconnected integrated circuits. In some cases, the integrated circuits may communicate through parallel interfaces, which simultaneously communicate multiple bits of data. In other cases, the integrated circuits may employ a serial interface, which sequentially communicates one bit of data at a time. In some cases, both parallel and serial interfaces, individual bits of communicated data may be differentially encoded.
In a computing system, the integrated circuits may have different power supply requirements, which may result in different output voltages being coupled to the integrated circuits' respective communication ports. Furthermore, variations in the properties of wiring traces on circuit boards as well as differences in power supply performance, may further contribute to differences in the power supply voltages supplied to the integrated circuits. Switching of output circuits during the transmission of data from one integrated circuit to another may further contribute to variations in the voltage levels of the power supplies.
To ensure overall system performance, additional margin may be added into the design to compensate for the variation in power supply voltage levels. In some cases, additional area and power may be consumed to ensure that sub-circuits within an integrated circuit can perform at level better than specified. By designing circuits in such a fashion, operation during periods of variation in power supply voltage levels may be maintained.